1. Field of the Invention
The present invention relates to a method of manufacturing a light emitting diode (LED) package.
2. Description of the Related Art
In general, a light emitting device includes a package having an LED mounted therein and a lens which covers the LED so as to enhance light emission efficiency within a predetermined orientation angle. Such a lens is previously manufactured by casting or the like, and is then coupled to the package through an adhesive. However, since the coupling force between the lens and the package is weak and the coupling operation is performed in a state where the package is exposed to the air, voids may be formed.
Recently, a transfer molding method is used, in which a lens-shaped molding member is formed on a package by using epoxy or silicon resin.
The transfer molding method which forms a molding member by using resin has been disclosed in US Patent No. 2003-0168720 tilted “Semiconductor device and manufacturing method for the same”.
Hereinafter, referring to FIG. 1, a method of forming a molding member disclosed in US Patent No. 2003-0168720 will be described in detail.
FIG. 1 is a process diagram for explaining a conventional method of forming a molding member. First, a metal plate is perforated so as to form a lead frame having a plurality of metal leads (not shown), an air vent frame 303, and an injection frame 305. At this time, the lead frame is formed by a pressing process such that ends of the metal leads are positioned under the frames 303 and 305.
Next, a package support portion (package main body) 304 is formed by injection molding. At this time, the package main body 304 is formed by inserting and molding a heat sink 302 and the lead frame in a die. The package main body 304 has recesses which expose the ends of the metal leads and the heat sink 302. Further, the package main body 304 has gates 306 adjacent to the frames 303 and 305.
Then, an LED 301 is mounted on the heat sink 302, and is electrically connected to the metal leads through wire bonding.
Subsequently, a predetermined surface of an upper die 401 is pressurized so as to be positioned adjacent to the upper surface of the package main body 304. The upper mold 401 is molded so as to have a trench for guiding an injection-molded mold material, a trench for guiding gas, and recesses and protrusions for forming a molding member into a desired shape. The mold material flows to the gate 306 along the upper surface of the injection frame 305, and gas is discharged along the upper surface of the air vent frame 303.
Accordingly, as a space 403 is filled with the mold material, a molding member is formed in a desired shape.
When the space 403 is substituted with the mold material by using the transfer molding method, the gate 306 at the air vent frame 303 may be clogged with the mold material before the space 403 is completely filled with the mold material.
Accordingly, the gas within the space 403 is not perfectly discharged, but may be captured in the mold material, thereby forming voids. The voids may not only cause solidification defects of the mold member, but also reduce uniformity and efficiency of light emitted through the mold member.